Vedecký časopis

48 2009

Journal of Food and Nutrition Research
Súhrny čísla 1 / 2009

Evaluation of phenolic compounds degradation in virgin olive oil during storage and heating
Journal of Food and Nutrition Research, 48, 2009, č. 1, s. 31-41

Despina Daskalaki, Department of Chemistry, Section of Industrial and Food Chemistry, University of Ioannina, Ioannina 45110, Greece. Tel.: 0030 2651098345, fax: 0030 2651098795, e-mail: mtasioul@cc.uoi.gr

Súhrn: Virgin olive oil is oil with a high biological value, due to its polyphenol content. Virgin olive oils were subjected to heat treatment simulating common domestic processing, including boiling, frying and storage. These processes can affect the phenolic compounds content of oils to a certain degree, depending on each one treatment. Thermal oxidation of oils at 180 °C (frying) caused a significant decrease (p < 0.005) in hydroxytyrosol derivatives (60% reduction after 30 min and 90% reduction after 60 min) and, to a lower degree, in tyrosol derivatives. No changes were observed in the content of lignans (p > 0.005). On the other hand, thermal oxidation of oils at 100 °C (boiling) for 2 h caused a decrease by less than 20% in all classes of phenolic compounds. The reduction of phenolic compounds during storage under environmental conditions was correlated with the peroxide value. When the peroxide value did not exceed the level of 20 meq.kg-1, as was recorded for low linoleic acid oils and low oxygen availability at the bottles’ headspace, a degree of reduction of approximately 30% in hydroxytyrosol derivatives and 10% in tyrosol derivatives was observed, while lignans remained unchanged. Finally, during both heating and storage under environmental conditions, the evolution of oxidized phenolic compounds was observed. The structures of these oxidized products were confirmed by HPLC-MS.

Kľúčové slová: virgin olive oil; phenolic compounds degradation; heating; storage; stability; oxidized phenols, HPLC-MS

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